Microcurrent Stimulation (MCS) therapy is a noninvasive procedure that involves stimulating the retina and nerve fibers with very low intensity electrical current using a Food and Drug Administration (FDA) approved electrical stimulation device. It is theorized that MCS Therapy works by increasing intracellular ATP (adenosine triphosphate) concentrations, enhancing protein synthesis, and stimulating the cells ability to absorb nutrients. Through these mechanisms, MCS therapy improves RPE (retinal pigment epithelium) efficiency and thereby may restore and/or improve retinal function.
Cheng, et al. disclosed increasing ATP levels from 300% to 500% through electrostimulation of the rat tissue with current levels from 50 to 1,000 μA. “The Effects of Electrical Currents on ATP Generation, Protein Synthesis, and Membrane Transport”, Clinical Orthopaedics and Related Research, No. 171, November–December, 1982.
ATP is synthesized in the mitochondria process known as the Kreb's Cycle, the sequence of reactions in the mitochondria that complete the oxidation of glucose in respiration. Kroll and Guerrieri have shown that there are age related changes in mitochondrial metabolism resulting in a decrease of the ATP synthase activity in the retina with age. Guerrieri has gone further to show functional and structural differences of the mitochondria F0F1 ATP synthase complex in aging rats. It is theorized that many retinal diseases, at least in part, are due to a decrease in mitochondria function and the subsequent decrease in intracellular ATP. This decrease in mitochondria function results from free radical damage and the mutation of mitochondria DNA (mtDNA). It is interesting to note the genetic link between ATP and retinal disease. ATP Synthase (ATPase) is an enzyme which catalyzes the synthesis of ATP. A genetic defect in the ATPase 6 Gene has now been implicated in retinitis pigmentosa.
A variety of devices and procedures are used to perform MCS therapy. For example, U.S. Pat. No. 5,522,864 proposes that macular degeneration or other ocular pathology may be treated by placing a positive electrode of a direct microcurrent source in contact with the closed eyelid of the subject and placing a negative electrode away from the eye of the subject, preferably on the neck of the subject. These electrodes apply a constant direct current of 200 microamps for approximately 10 minutes.
U.S. Pat. No. 6,275,735 discloses a method and apparatus for applying a microcurrent signal to a body part to combat visual system diseases such as macular degeneration. A controller outputs data words to a digital-to-analog converter (DAC), which produces analog electrical signals that are provided to a voltage controlled oscillator (VCO). The VCO generates electrical signals having frequencies that depend on the signals received from the DAC. The user holds an electrical probe to a body part to be treated and a microcurrent signal having the frequency produced by the VCO is applied via the probe to the body part. The first data word causes a first relatively low frequency (0 to 400 Hz) microcurrent signal to be applied and a second data word causes a second relatively high frequency (500 to 2 MHz) microcurrent signal to be applied.
While many attempts have been made to use MCS therapy to treat macular degeneration and other ocular diseases, existing methods and apparatuses proposed for this purpose have, to date, been ineffective. Accordingly, a need exists for an effective approach to MCS therapy that enables conditions of macular degeneration and other ocular diseases to be improved or at least stabilized.